CN119708703A

CN119708703A - Low-density, high-flame-retardant and high-temperature-boiling-resistant polypropylene insulating material for automobile wires and preparation method thereof

Info

Publication number: CN119708703A
Application number: CN202411981674.4A
Authority: CN
Inventors: 周城; 陈夏; 吴昆�
Original assignee: Cgn Delta Jiangsu Plastics Co ltd
Current assignee: Cgn Delta Jiangsu Plastics Co ltd
Priority date: 2024-12-31
Filing date: 2024-12-31
Publication date: 2025-03-28

Abstract

The invention discloses a low-density, high-flame-retardant and high-temperature-boiling-resistant polypropylene insulating material for an automobile wire and a preparation method thereof, wherein the raw materials comprise 40-70 parts of polypropylene resin, 5-40 parts of elastomer resin, 5-10 parts of functional auxiliary agent, 0.5-1.5 parts of antioxidant, 0.5-1.5 parts of copper inhibitor and 20-150 parts of flame retardant. The preparation method mainly comprises the steps of firstly carrying out first-time processing through a reciprocating machine, carrying out first-time dispersion on components such as the flame retardant by utilizing the softer shearing characteristic of the reciprocating machine, and secondly carrying out second-time processing on products in the previous step through a double-screw extruder, so that the uniformity of the dispersion of the flame retardant is ensured, and the flame retardant uniformity of the products is improved. In addition, the product can also be produced by a processing mode of flame retardant master batch and secondary processing extrusion, but the principle is similar to the processing mode and has the consistency of effects. The invention successfully solves the problems of high density and hydrolysis intolerance of the flame-retardant polypropylene insulating material through system compounding, and simultaneously has high-efficiency flame-retardant property, so that the flame-retardant polypropylene insulating material is more suitable for the use requirement of the flame-retardant insulating material for automobile wires.

Description

Low-density, high-flame-retardant and high-temperature-boiling-resistant polypropylene insulating material for automobile wires and preparation method thereof

Technical Field

The invention relates to the field of insulating materials for wires and cables, in particular to a low-density, high-flame-retardant and high-temperature-boiling-resistant polypropylene insulating material for automobile wires and a preparation method thereof.

Background

In recent years, cross-linked flame-retardant polyolefin insulating materials have been widely developed and applied in the fields of automobile electronic wires, high-voltage wires in automobiles and the like. However, the materials need to undergo crosslinking procedures such as water boiling, irradiation and the like before use, which not only significantly increases the production time and cost of the cable, but also causes small molecules generated in the crosslinking process to influence the electrical performance of the insulating material to a certain extent.

In contrast, polypropylene is used as an insulating material and has the characteristics of excellent insulating property, high temperature resistance level, recycling and the like. When used as an insulating material, polypropylene can simplify the processing process, reduce the cost, increase the production rate, and greatly increase the cable length, which can lead to the far-reaching super-crosslinked polyethylene.

Furthermore, according to the new revised standard requirements, the flame-retardant time of the cable has been shortened to 30 seconds, which presents a new challenge for the flame retardant properties of the material. However, flame retardants used in conventional cables, such as magnesium hydroxide, aluminum hydroxide, halogen-containing flame retardants, etc., may cause deterioration of hydrolysis resistance of the thermoplastic cable and decrease of insulation volume resistivity when the flame retardant content is further increased. At the same time, the increase in material density further increases the cost of the cable.

Therefore, the invention develops the thermoplastic flame-retardant polypropylene cable insulating material with low density and hot water hydrolysis resistance aiming at the problems of irrecoverable, high density, possible halogen and the like of the common flame-retardant polyolefin material for the automobile wire, and simultaneously further improves the flame retardance of the product so as to be capable of meeting the requirements of customers.

Disclosure of Invention

The invention aims to provide a low-density, high-flame-retardant and high-temperature-boiling-resistant polypropylene insulating material for an automobile wire and a preparation method thereof.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the low-density, high-flame-retardant and high-temperature-boiling-resistant polypropylene insulating material for the automobile wire comprises the following raw materials in parts by weight:

according to a further technical scheme, the polypropylene resin is copolymerized polypropylene, the melt index is 0.1-10 g/10min (preferably 2-4 g/10 min), the melting point is greater than or equal to 160 ℃, only one melting peak exists, the crystallization peak temperature is greater than or equal to 110 ℃, only one cooling crystallization peak exists, and the flexural modulus is less than or equal to 1500MPa.

According to a further technical scheme, the elastomer is an olefin block copolymer or/and hydrogenated butylbenzene, wherein,

The melting temperature of the olefin block copolymer is greater than or equal to 120 ℃, the room temperature compression set is less than or equal to 50%, and the compression set is preferably 20-30%;

The hydrogenated butylbenzene is provided with a star structure or a long carbon chain branching structure, and the solubility parameter is 7-9;

When the elastomer is a mixture of an olefin block copolymer and hydrogenated styrene-butadiene, the mass ratio of the olefin block copolymer to the hydrogenated styrene-butadiene is 100:0-0:100, preferably 50:50-20:80.

According to a further technical scheme, the functional auxiliary agent is a beta-type nucleating agent with a toughening function.

According to a further technical scheme, the functional auxiliary agent is one or a mixture of more than or equal to 5 per mill, preferably 5 to 1.5 per mill of maleic anhydride in the functional auxiliary agent, and the melt index is less than or equal to 8g/10min, preferably 3 to 5g/10min.

According to a further technical scheme, the functional auxiliary agent is a macromolecular carbonizing agent with a hyperbranched structure and/or a silica structure.

According to a further technical scheme, the flame retardant is one or more of a flame retardant with an oxazine ring structure, a phosphazene flame retardant, a phosphorus nitrogen flame retardant, a silicon flame retardant, a flame retardant synergist, a carbon forming agent and an expansion flame retardant, wherein the phosphorus content is more than or equal to 20%, the nitrogen content is more than or equal to 40%, and the melting temperature is more than or equal to 100 ℃.

Wherein the flame retardant with phosphorus and nitrogen elements is modified by modification of molecules containing silicon oxygen, alkyl, alkoxy, amino and/or tetrabutyl titanate, isopropyl stearyl titanate and chelate titanate, and the number of times of modification or coating of the flame retardant is more than or equal to one time.

The silicon flame retardant is modified by alkyl, alkenyl, amino and isocyanate groups so as to improve the compatibility of other base materials.

Furthermore, the invention also discloses a preparation method of the low-density, high-flame-retardant and high-temperature-resistant poaching-resistant polypropylene insulating material for the automobile wire, which comprises the following steps:

Firstly, adding polypropylene resin, elastomer resin, functional auxiliary agent, flame retardant, antioxidant and copper inhibitor into a BUSS machine according to a proportion, respectively utilizing a granule weightlessness scale, a powder weightlessness scale and an auxiliary agent scale to perform blanking according to a preset proportion, and performing melt extrusion, cooling, granulating and drying to obtain a first product, wherein the temperature of a melt extrusion micelle is 190-210 ℃;

And secondly, adding the first product into a double-screw extruder for secondary processing to ensure the uniformity of flame retardation dispersion, and finally obtaining the low-density, high-flame retardation and high-temperature boiling-resistant polypropylene insulating material for the automobile wire through melt extrusion, cooling, granulating and drying, wherein the extrusion processing temperature is 130-190 ℃.

According to a further technical scheme, in the first step, the water content of the dried first product is lower than 200ppm.

In the second step, the processing temperature of the first section of the twin-screw extruder is 130 ℃ and the processing temperature of the second section is 170-190 ℃.

According to the further technical scheme, the double-screw extruder is provided with the following configuration foundation that the shearing block angles are 45 degrees, 60 degrees and 90 degrees, and meanwhile, a large-lead conveying block and a reverse rotation module are arranged at the middle and rear section of the screw.

As used herein, the terms "comprising," "including," "having," and the like are intended to be open-ended terms, meaning including, but not limited to.

The term (terms) as used herein generally has the ordinary meaning of each term as used in this field, in this disclosure, and in the special context, unless otherwise noted. Certain terms used to describe the present disclosure are discussed below, or elsewhere in this specification, to provide additional guidance to those skilled in the art in connection with the description herein.

The working principle and the advantages of the invention are as follows:

(1) The invention solves the problems of non-recycling, high density, poor flame retardance and non-environmental protection of the existing flame-retardant polyolefin insulating material.

(2) The invention solves the problem of poor temperature resistance grade caused by low melting point of polyethylene by adopting the polypropylene resin with higher temperature resistance grade. The polyethylene used for making the insulating material with the same function is known to be low-density polyethylene or linear low-density polyethylene, the melting point of the polyethylene is generally below 120 ℃, the temperature resistance level can be improved only by a crosslinking mode, but after crosslinking, the material cannot be melted, plasticized and molded, cannot be recycled, can only be treated by modes of burning, burying and the like, and the polypropylene resin adopted in the technical scheme of the invention can avoid the occurrence of the conditions.

(3) The common halogen-free inorganic flame retardant, such as magnesium hydroxide and aluminum hydroxide, has good flame retardant effect only when the addition amount exceeds 150 parts, however, the specific addition amount not only reduces the mechanical property, the electrical property and the high-temperature boiling resistance of the material, but also further increases the density of the material. While halogen flame retardants have good flame retardant effect, hydrogen halide gas generated during combustion is extremely harmful, and the harm to people and objects is far greater than the harm of fire. Based on the problems, the technical scheme of the invention adopts the phosphorus-nitrogen flame retardant subjected to coating treatment, so that the corrosion of moisture can be less isolated, and the hydrolysis resistance of the material is improved, and meanwhile, the organic phosphorus-nitrogen flame retardant has the advantages of physical isolation (generated gas is diluted or oxygen is isolated), decomposition and heat absorption (small molecules generated during the severe decomposition of the flame retardant can take away a large amount of heat so as to reduce the combustion temperature), carbonization promotion (generated carbonized layers further isolate high polymers from fire sources so as to inhibit combustion), and the flame retardant effect can be realized only when the magnesium hydroxide and the aluminum hydroxide are compounded to form the synergistic flame retardant. More importantly, due to high-efficiency flame retardant efficiency, the addition amount of the organic phosphorus nitrogen flame retardant is only 1/4-1/5 of the amount of the magnesium hydroxide and aluminum hydroxide flame retardant, and the material density is obviously reduced.

In conclusion, the invention successfully solves the problems of high density and hydrolysis resistance of the flame-retardant polypropylene insulating material through system compounding, and simultaneously has high-efficiency flame-retardant property, so that the flame-retardant polypropylene insulating material is more suitable for the use requirement of the flame-retardant insulating material for automobile wires.

Detailed Description

The invention is further described below with reference to examples:

Examples the present invention will be described in detail below, and it will be apparent to those skilled in the art from this disclosure that variations and modifications can be made in the techniques taught herein without departing from the spirit and scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. Singular forms such as "a," "an," "the," and "the" are intended to include the plural forms as well, as used herein.

TABLE 1 insulating compositions of examples 1-6

The following preparation methods for each example and comparative example are described below according to the component formulations in table 1:

the preparation method of example 1:

Firstly, 80 parts of polypropylene resin (K8003), 20 parts of olefin block copolymer (OBC 9000) and 5 parts of maleic anhydride grafted EVA (VA 1801) are uniformly shaken by a low-speed mixer, then a pellet weightlessness scale is added, 30 parts of compound phosphorus-nitrogen flame retardant (melamine cyanurate/modified aluminum hypophosphite=1/5) and 5 parts of carbonization agent (hyperbranched resin) are uniformly shaken, then a powder weightlessness scale is added, 1.5 parts of antioxidant (1010+DSTP+1024) and 0.2 part of beta nucleating agent are uniformly shaken, then an auxiliary agent scale is added, and then a first product is obtained through melt extrusion, cooling, pelleting and drying, in addition, the temperature of a melt extrusion rubber ball is ensured to be 190-210 ℃ in the processing process, and the scorching phenomenon of the rubber ball caused by overhigh temperature is avoided.

And secondly, adding the first product into the weightless scale of the double-screw extruder again for secondary processing treatment so as to ensure the uniformity of flame retardant dispersion.

The secondary processing temperature is 130-170-175-180-190 ℃, and finally, the polypropylene insulating material with low density, high flame retardance and high temperature resistance for the automobile wire is obtained through melt extrusion, cooling, pelleting and drying.

The preparation method of example 2:

Firstly, 60 parts of polypropylene resin (K8003), 20 parts of olefin block copolymer (OBC 9000), 20 parts of branched SEBS and 5 parts of maleic anhydride grafted SEBS (FG 1901) are uniformly shaken by a low-speed mixer, then the weight loss of granules is added, 40 parts of compound phosphorus-nitrogen flame retardant (melamine cyanurate/modified aluminum hypophosphite=1/5), 5 parts of carbonizing agent (hyperbranched resin) are uniformly shaken, then the weight loss of powder is added, 1.5 parts of antioxidant (1010+DSTP+1024) and 0.2 part of beta nucleating agent are uniformly shaken, then the auxiliary agent is added, and then the first product is obtained through melt extrusion, cooling, granulation and drying, in addition, the temperature of a melt extrusion glue mass is ensured to be 190-210 ℃ in the processing process, and the scorching phenomenon of the glue mass caused by overhigh temperature is avoided.

The preparation method of example 3:

Firstly, 40 parts of polypropylene resin (K8003), 20 parts of olefin block copolymer (OBC 9000), 40 parts of branched SEBS, 5 parts of maleic anhydride grafted SEBS (FG 1901), shaking uniformly by a low-speed mixer, adding a granule weightlessness scale, 50 parts of compound phosphorus-nitrogen flame retardant (melamine cyanurate/modified aluminum hypophosphite=1/5), 5 parts of carbonization agent (hyperbranched resin), shaking uniformly, adding a powder weightlessness scale, 1.5 parts of antioxidant (1010+DSTP+1024), 0.2 part of beta nucleating agent, shaking uniformly, adding an auxiliary agent, further obtaining a first product by melt extrusion, cooling, granulating and drying, and ensuring that the temperature of a melt extrusion glue mass is 190-210 ℃ in the processing process, so as to avoid scorching of the glue mass caused by overhigh temperature.

The preparation method of example 4:

Firstly, 20 parts of polypropylene resin (K8003), 30 parts of olefin block copolymer (OBC 9000), 50 parts of branched SEBS and 5 parts of maleic anhydride grafted EVA (VA 1801) are uniformly mixed by a low-speed mixer, then the mixture is added with a granule weightlessness scale, 30 parts of compound phosphorus-nitrogen flame retardant (melamine cyanurate/modified aluminum hypophosphite=1/5), 5 parts of carbonizing agent (hyperbranched resin) are uniformly mixed, then the mixture is added with a powder weightlessness scale, 1.5 parts of antioxidant (1010+DSTP+1024) and 0.2 part of beta nucleating agent, and then the mixture is added with an auxiliary agent after being uniformly mixed, and then the mixture is subjected to melt extrusion, cooling, granulation and drying to obtain a first product, and in addition, the temperature of a melt extrusion glue mass is ensured to be 190-210 ℃ in the processing process, so that the scorching phenomenon of the glue mass caused by overhigh temperature is avoided.

The preparation method of comparative example 1:

Firstly, 80 parts of polypropylene resin (K8003), 20 parts of olefin block copolymer (OBC 9000) and 5 parts of maleic anhydride grafted EVA (VA 1801) are uniformly shaken by a low-speed mixer, then a pellet weightlessness scale is added, 130 parts of compound phosphorus-nitrogen flame retardant (melamine cyanurate/modified aluminum hypophosphite=1/5) and 5 parts of carbonization agent (hyperbranched resin) are uniformly shaken, then a powder weightlessness scale is added, 1.5 parts of antioxidant (1010+DSTP+1024) and 0.2 part of beta nucleating agent are uniformly shaken, then an auxiliary agent scale is added, and then a first product is obtained through melt extrusion, cooling, pelleting and drying, in addition, the temperature of a melt extrusion rubber ball is ensured to be 190-210 ℃ in the processing process, and the scorching phenomenon of the rubber ball caused by overhigh temperature is avoided.

Table 2 Table 1-6 Performance List:

according to the material performance results, after the special-treated phosphorus-nitrogen flame retardant and the functional performance auxiliary agent are added, the automobile wire can pass through a water boiling test at 85 ℃ for 35 days, the volume resistivity of the automobile wire is not lower than 108 Ω & cm, and meanwhile, the flame-retardant time of the cable is within 20 seconds, so that the standard requirement is met. Further, the density is reduced by at least 25% as compared with the case of adding an inorganic flame retardant such as magnesium hydroxide. Other properties of the material can meet other requirements of the standard through detection. In contrast, the comparative examples have poor compatibility between the resin and the flame retardant due to the large filling amount of the magnesium hydroxide flame retardant, so that the electric properties, density, hydrolysis resistance, mechanical properties and the like are inferior to those of the examples of the present invention. In the comprehensive view, the invention successfully develops the low-density, high-flame-retardance and water-resistant thermoplastic polypropylene insulating material, and can be used for the production and the use of automobile wire harnesses.

The above embodiments are provided to illustrate the technical concept and features of the present invention and are intended to enable those skilled in the art to understand the content of the present invention and implement the same, and are not intended to limit the scope of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be construed to be included in the scope of the present invention.

Claims

1. A low-density, highly flame-retardant, high-temperature boiling-resistant polypropylene insulation material for automotive wires, characterized in that its raw materials include the following components in parts by weight:

Polypropylene resin 40-70 parts;

Elastomer resin 5-40 parts;

Functional additives 5~10 parts;

Antioxidant 0.5~1.5 parts;

Anti-copper agent 0.5~1.5 parts;

Flame retardant 20~150 parts.

2. A low-density, highly flame-retardant, high-temperature boiling-resistant polypropylene insulation material for automotive wires according to claim 1, characterized in that: the polypropylene resin is copolymer polypropylene, with a melt index of 0.1~10g/10min, a melting point greater than or equal to 160°C, and only one melting peak; the crystallization peak temperature is greater than or equal to 110°C, and only one cooling crystallization peak; the flexural modulus is less than or equal to 1500MPa.

3. A low-density, highly flame-retardant, high-temperature boiling-resistant polypropylene insulation material for automotive wires according to claim 1, characterized in that: the elastomer is an olefin block copolymer and/or hydrogenated butadiene styrene;

The melting temperature of the olefin block copolymer is greater than or equal to 120° C., and the room temperature compression permanent deformation is less than or equal to 50%;

The hydrogenated butylbenzene is a hydrogenated butylbenzene with a star structure or a long carbon chain branched structure, and its solubility parameter is 7 to 9;

When the elastomer is a mixture of an olefin block copolymer and hydrogenated butadiene styrene, the mass ratio of the olefin block copolymer to the hydrogenated butadiene styrene is 100:0 to 0:100.

4. The low-density, highly flame-retardant, high-temperature boiling-resistant polypropylene insulation material for automotive wires according to claim 1, characterized in that the functional additive is a β-type nucleating agent with a toughening function.

5. A low-density, highly flame-retardant, high-temperature boiling-resistant polypropylene insulation material for automotive wires according to claim 1, characterized in that: the functional additive is a mixture of one or more of maleic anhydride grafted hydrogenated butadiene styrene, maleic anhydride grafted vinyl polyolefin elastomer, maleic anhydride grafted propylene polyolefin elastomer, maleic anhydride grafted EPDM, maleic anhydride grafted EVA or EBA, and maleic anhydride grafted EVM; the maleic anhydride content in the functional additive is greater than or equal to 5‰, preferably 5‰~1.5%; the melt index is less than or equal to 8g/10min, preferably 3~5g/10min.

6. The low-density, highly flame-retardant, high-temperature boiling-resistant polypropylene insulation material for automotive wires according to claim 1, characterized in that the functional additive is a macromolecular carbon-forming agent with a hyperbranched structure and/or a silicon-oxygen structure.

7. A low-density, highly flame-retardant, high-temperature boiling-resistant polypropylene insulation material for automotive wires according to claim 1, characterized in that: the flame retardant is one or more of a flame retardant with azine ring structure, phosphazene flame retardant, phosphorus nitrogen flame retardant, silicon flame retardant, flame retardant synergist, carbon former, and intumescent flame retardant, wherein the phosphorus content is greater than or equal to 20%, the nitrogen content is greater than or equal to 40%, and the melting temperature is greater than or equal to 100°C;

Among them, the flame retardants containing phosphorus and nitrogen elements are all modified by molecules containing silicone, alkyl, alkoxy, amino and/or tetrabutyl titanate, isopropyl titanate, isopropyl stearoyl titanate, and chelate titanate, and the flame retardant is modified or coated more than or equal to once;

Wherein, the silicon flame retardant is modified by alkyl, alkenyl, amino and isocyanate groups.

8. A method for preparing a low-density, highly flame-retardant, high-temperature boiling-resistant polypropylene insulation material for automotive wires, characterized in that: the method is used to prepare the low-density, highly flame-retardant, high-temperature boiling-resistant polypropylene insulation material for automotive wires as claimed in any one of claims 1 to 7, and the method comprises:

Step 1: Add polypropylene resin, elastomer resin, functional additives, flame retardants, antioxidants, and anti-copper agents into a BUSS machine in proportion, use a pellet weight loss scale, a powder weight loss scale, and an additive scale to feed the materials in a predetermined proportion, and obtain the first product by melt extrusion, cooling, granulation, and drying; wherein the temperature of the melt extruded gel mass is between 190 and 210°C;

Step 2: Add the first product into a twin-screw extruder for secondary processing, and obtain the low-density, highly flame-retardant, high-temperature boiling-resistant polypropylene insulation material for automotive wires through melt extrusion, cooling, granulation and drying; wherein the extrusion processing temperature is 130~190℃.

9. The preparation method according to claim 8, characterized in that: in step 1, the water content of the first product after drying is less than 200 ppm.

10. The preparation method according to claim 8, characterized in that: in step 2, during the extrusion process, the processing temperature of the twin-screw extruder in the initial stage is 130°C, and the processing temperature of the latter stage is 170-190°C.